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Coelacanth Genome Project

The Comorese coelacanth, Latimeria chalumnae, is a member of the ancient group of lobe-finned fishes, all of which were thought to have been extinct since the Late Cretaceous period, seventy million years ago. However, in 1938, a South African museum curator discovered an unusual fish among the catch of a local trawler. This fish was curiously similar to fossils from the Cretaceous period and was soon identified as a modern coelacanth. A second species, the Indonesian coelacanth, was discovered in 1998.

The coelacanth has fleshy fins that resemble primordial limbs and is used to study the early adaptations that facilitated the sea-to-land transition. It also serves as an important outgroup to the land vertebrates. The coelacanth is known to have an unusually slow rate of molecular evolution and so its sequence will be particularly useful in the search for deeply conserved non-coding elements. It is also hypothesized that the coelacanth genome could have retained genes lost in other lineages and might be a repository of ancient repetitive elements.

The Broad Institute has generated a high quality draft from a Comorese coelacanth. RNA-seq is being produced to annotate the genome. The sequence of the coelacanth genome will help us to understand our distant aquatic ancestry and will be useful in the reconstruction of the fish phylogeny.

This genome will also be very informative in the annotation of the human genome, since it did not undergo the teleost fish whole genome duplication, making it especially valuable in the search for highly conserved sequences.